[Release] Prepare for v0.13.1 (#1809)

CHANGELOG.md

 # Change Log
 
+## v0.13.1 - 2022-08-16
+
+([full changelog](https://github.com/executablebooks/jupyter-book/compare/v0.13.0...8a74127748066eac5e0e788a584cb31d18b66058))
+
+This minor release includes improvements to the project documentation and includes the following fixes:
+
+### Fixes and Maintenance
+
+1. [#1750](https://github.com/executablebooks/jupyter-book/pull/1750) improves compatibility with sphinx>=5.
+2. [#1774](https://github.com/executablebooks/jupyter-book/pull/1774) fixes an issue that enables math when using the `singlehtml` builder
+
+
 ## v0.13.0 - 2022-06-02
 
 ([full changelog](https://github.com/executablebooks/jupyter-book/compare/v0.12.3...a2d441633d5aafed4e94bbc544183cf866213f3a))

jupyter_book/__init__.py

 """Build a book with Jupyter Notebooks and Sphinx."""
 
-__version__ = "0.13.0"
+__version__ = "0.13.1"
 
 
 # We connect this function to the step after the builder is initialized